Trying to correct a fear reaction is unlikely to work (as you stated) also petting and comforting them is also not going to work because you are telling them their aggressive fearful reaction is allowed.
You will need to work to having them remain calm, and then praising them for being calm when the other dogs pass, you can also simply start by distracting them with food at first. When you first pot a dog try getting off to the side, or going into a yard and get the dogs to focus on you.
Did your first dog have these reactions or only after the new dog arrived? Who seems to be the instigator? You may need to work 1 on 1 with Bruno to improve his behavior. Usually one dog is the problem and the other just follows suit, manage the dog triggering the reactions and the second dog will likely follow quite quickly.